This invention relates to a rotary internal combustion engine, and in particular a rotary diesel engine. The invention relates to the type of rotary internal combustion engines having a pair of substantially identical rotating members cooperating with a stationary fuel supplying and exhaust gas removing shaft, the rotating members having radially reciprocal piston and cylinder arrangements associated therewith. It is believed that the present invention has several advantages over prior art proposals which advantages make the invention a more practical structure for actual use, especially with diesel engines.
According to the present invention, a large heat transfer area is provided for the rotating members which heat transfer area facilitates cooling of the pistons and cylinders and thereby lengthens the life of the pistons and cylinders under the high temperature conditions normally prevalent in a diesel engine. The large heat transfer area is provided in two different manners--the rotary assemblies include a plurality of arms that extend radially outwardly from a hub portion which surrounds the stationary shaft, and on the radially extendingly arms are provided a plurality of axially spaced, radially extending cooling fins. Additionally, adverse effects on the component parts of the structure due to heat are minimized by providing an arcuate exhaust port in the stationary shafts that extends over a substantial portion of the arc of travel of the rotary devices (more than 90.degree.) and by providing internal surface means that move each piston radially inwardly during the exhaust stroke in a constant gradual manner in order to minimize the adverse effects of the high temperature gases being exhausted on the rotor passageways and the stationary exhaust shaft. Typically, the exhaust stroke is longer than either the intake, compression, or power stroke.
The radially extending arm configuration according to the present invention also has other advantages besides the heat dissipating characteristics thereof. By the provision of radially extending arms instead of small notches formed in rotating wheels (as in U.S. Pat. No. 3,043,234) according to the present invention a much larger surface area is provided for the pistons to act on when imparting rotational forces to the assemblies, which leads to a more efficient transfer of the force from the radially reciprocal pistons to the rotating assemblies. Also, the arm configuration of the rotary assemblies minimizes the number of piston and cylinder arrangements that need be provided in order for efficient operation of the engine, and since the piston and cylinder arrangements are expensive component parts of an engine thereby minimizes the cost of the engine. For instance, the rotary assemblies can be constructed so that only three arms are provided, resulting in a simple yet efficient operable structure.
According to the present invention, a rotary engine is provided comprising a pair of spaced parallel stationary intake-exhaust shafts; a pair of substantially identical rotor assemblies, one assembly mounted for rotation about each of the stationary shafts and each of the assemblies including a hub portion immediately surrounding a stationary shaft, a plurality (i.e. three) of arms extending radially outwardly from the hub portion, a radially extending cylinder formed in each of the arms, a radially extending passageway leading from the stationary shaft to each cylinder, a radially reciprocal piston disposed in each cylinder; means for spacing the stationary shafts and mounting the rotor assembly so that upon rotation of the rotor assemblies each piston associated with each of the rotor assemblies will engage the hub of the other assembly upon completion of the compression stroke of the piston, and then will engage an arm of the other assembly and impart a rotational force thereto upon radial movement of the piston during a power stroke after compression; and casing means associated with the rotor assemblies for effecting radial movement of the pistons after completion of a power stroke so that gases from the cylinders are exhausted to the intake-exhaust stationary shaft. A plurality of axially spaced, radially extending cooling fins are associated with each of the rotor assemblies. Additionally, the remote ends of each of the pistons are arcuate and the termination portions of each of the arms have arcuate portions formed in a continuous arc with the piston when the piston is in its most radially inward position. The intake-exhaust stationary shaft has an arcuate exhaust port formed therein that extends more than 90.degree., and the casing means has first internal surface means for inwardly radially biasing the pistons after completion of a power stroke to exhaust gases from the cylinders so that the exhaust stroke takes place over an arc of travel of more than 90.degree. during rotation of the rotor assemblies. The casing means may also comprise second internal surface means that allow essentially free radial movement of the pistons during the majority of the intake stroke thereof.
The engine according to the invention is preferably a diesel engine, and a method of driving a power shaft using the rotary diesel engine according to the invention includes the steps of injecting fuel into each cylinder during an intake stroke, inwardly radially moving the piston after injection of fuel into the cylinder to compress the injected fuel until ignition of the fuel takes place by compression of the fuel, during the power stroke of a piston associated with one assembly imparting rotation to the other assembly in a direction opposite to the rotation of the one assembly, and radially inwardly biasing each piston after completion of a power stroke thereby to exhaust gases from the cylinder associated therewith, the radial inward biasing taking place over an arc of more than 90.degree. during rotation of the rotor assemblies, the exhaust stroke being over a greater arcuate travel than either the intake, compression, or power stroke, and the exhausting of gases during the exhaust stroke being gradual during radial inward movement of the piston. These steps are then repeated during constant rotation of the assemblies.
It is the primary object of the present invention to provide a simple operable rotary internal combustion engine, especially a diesel engine. This and other objects of the invention will become clear from an inspection of the detailed description of the invention and from the appended claims.